High increase of Nichols-like clade circulating Treponema pallidum subsp. pallidum in Barcelona from 2021 to 2023.

Worldwide, more than 90% of contemporary syphilis strains belong to SS14-like clade. This study aimed to describe the molecular profile of circulating Treponema pallidum subsp. pallidum (TPA) strains in Barcelona, Spain, from 2021 to 2023 building upon our report in 2015 which showed that 94.8% of typed strains belonged to the SS14 clade. Multilocus sequence typing (MLST) was conducted on TPA-positive samples obtained from swab samples by sequencing the tp0136, tp0548, and tp0705 loci. Strains were classified as Nichols-like or SS14-like clade. Macrolide and tetracycline resistance­associated mutations were determined through analysis of 23S rDNA and 16S rRNA gene sequences. Of the 96 typeable samples, 47.9% belonged to SS14-like and 52.1% to the Nichols-like. Fourteen haplotypes were identified, with ST26 representing 43.8% of the samples, distributed across 11 haplotypes in the SS14-like and 3 haplotypes in the Nichols-like. All the samples showed macrolide resistance-associated mutations, while none exhibited tetracycline-associated mutations. Our findings revealed a substantial shift in the proportion of TPA clades within the Barcelona population from 2021 to 2023, characterized by a higher proportion of Nichols-like strains compared to 2015 and international trends. The varying temporal and geographical trends underscore the need for regular surveillance to understand regional variations in syphilis and strengthen control programs.

Epidemic of multiple Treponema pallidum strains in men who have sex with men in Japan: efficient multi-locus sequence typing scheme and indicator biomarkers.

BACKGROUND: The challenges in culturing Treponema pallidum have hindered molecular-biological analysis. This study aims to establish a molecular epidemiological analysis of syphilis among Japanese men who have sex with men (MSM) and to investigate the relationship between bacteremia and associated pathophysiology. METHODS: We used whole blood specimens from syphilis-diagnosed individuals in Tokyo, collected between February 2019 and June 2022. All individuals were MSM, and most were people with HIV (97.2%). We used a multi-locus sequence typing (MLST) scheme for epidemiological analysis. Sequences for MLST (TP0136, TP0548, and TP0705) were obtained. RESULTS: Out of 71 whole blood samples, 26 samples (36.6%) were positive for TP0136, and we sequenced three loci for MLST in 22 samples (31.0%). The most frequently detected sequence type (ST) was ST3 (n = 9), followed by ST6 (n = 6). Phylogenetic analysis revealed that 12 samples belonged to the SS14-like group (60%), and 8 samples belonged to the Nichols-like group (40%). Treponema pallidum subsp. endemicum (TEN), the cause of bejel was detected in three samples (12%). There was a significant association between TP0136 detection rate and C- reactive protein (CRP) (77.0% at a cut-off:0.5 mg/dL). CONCLUSION: Both SS14-like and Nichols-like strains were circulating concurrently, and TEN could have been sexually transmitted among MSM with HIV. Elevated CRP may indicate the presence of the pathogen in the blood.

Phosphorylated vimentin-triggered fibronectin matrix disaggregation enhances the dissemination of Treponema pallidum subsp. pallidum across the microvascular endothelial barrier.

Fibronectin (FN) is an essential component of the extracellular matrix (ECM) that protects the integrity of the microvascular endothelial barrier (MEB). However, Treponema pallidum subsp. pallidum (Tp) breaches this barrier through elusive mechanisms and rapidly disseminates throughout the host. We aimed to understand the impact of Tp on the surrounding FN matrix of MEB and the underlying mechanisms of this effect. In this study, immunofluorescence assays (IF) were conducted to assess the integrity of the FN matrix surrounding human microvascular endothelial cell-1 (HMEC-1) with/without Tp co-culture, revealing that only live Tp exhibited the capability to mediate FN matrix disaggregation in HMEC-1. Western blotting and IF were employed to determine the protein levels associated with the FN matrix during Tp infection, which showed the unaltered protein levels of total FN and its receptor integrin α5ß1, along with reduced insoluble FN and increased soluble FN. Simultaneously, the integrin α5ß1-binding protein-intracellular vimentin maintained a stable total protein level while exhibiting an increase in the soluble form, specifically mediated by the phosphorylation of its 39th residue (pSer39-vimentin). Besides, this process of vimentin phosphorylation, which could be hindered by a serine-to-alanine mutation or inhibition of phosphorylated-AKT1 (pAKT1), promoted intracellular vimentin rearrangement and FN matrix disaggregation. Moreover, within the introduction of additional cellular FN rather than other Tp-adhered ECM protein, in vitro endothelial barrier traversal experiment and in vivo syphilitic infectivity test demonstrated that viable Tp was effectively prevented from penetrating the in vitro MEB or disseminating in Tp-challenged rabbits. This investigation revealed the active pAKT1/pSer39-vimentin signal triggered by live Tp to expedite the disaggregation of the FN matrix and highlighted the importance of FN matrix stability in syphilis, thereby providing a novel perspective on ECM disruption mechanisms that facilitate Tp dissemination across the MEB.

Syphilis vaccine development: Aligning vaccine design with manufacturing requirements.

Syphilis, caused by Treponema pallidum subsp. pallidum, is a global health concern with increasing rates worldwide. Current prevention strategies, including screen-and-treat approaches, are not sufficient to resolve rising infection rates, emphasizing the need for a vaccine. Developing a syphilis vaccine necessitates a range of cross-disciplinary considerations, including essential disease-specific protection, technical requirements, economic feasibility, manufacturing constraints, public acceptance, equitable vaccine access, alignment with global public vaccination programs, and identification of essential populations to be vaccinated to achieve herd immunity. Central to syphilis vaccine development is prioritization of global vaccine availability, including access in low- to middle-income settings. Various vaccine platforms, including subunit, virus-like particle (VLP), mRNA, and outer membrane vesicle (OMV) vaccines, present both advantages and challenges. The proactive consideration of both manufacturing feasibility and efficacy throughout the pre-clinical research and development stages is essential for producing an efficacious, inexpensive, and scalable syphilis vaccine to address the growing global health burden caused by this disease.

Bright New Resources for Syphilis Research: Genetically Encoded Fluorescent Tags for Treponema pallidum and Sf1Ep Cells.

The recently discovered methodologies to cultivate and genetically manipulate Treponema pallidum subsp. pallidum (T. pallidum) have significantly helped syphilis research, allowing the in vitro evaluation of antibiotic efficacy, performance of controlled studies to assess differential treponemal gene expression, and generation of loss-of-function mutants to evaluate the contribution of specific genetic loci to T. pallidum virulence. Building on this progress, we engineered the T. pallidum SS14 strain to express a red-shifted green fluorescent protein (GFP) and Sf1Ep cells to express mCherry and blue fluorescent protein (BFP) for enhanced visualization. These new resources improve microscopy- and cell sorting-based applications for T. pallidum, better capturing the physical interaction between the host and pathogen, among other possibilities. Continued efforts to develop and share new tools and resources are required to help our overall knowledge of T. pallidum biology and syphilis pathogenesis reach that of other bacterial pathogens, including spirochetes.

Molecular investigation of Treponema pallidum strains associated with ocular syphilis in the United States, 2016-2020.

Ocular syphilis is a serious complication of Treponema pallidum infection that can occur at any stage of syphilis and affect any eye structure. It remains unknown if certain T. pallidum strains are associated with ocular infections; therefore, we performed genotyping and whole genome sequencing (WGS) to characterize strains from patients with ocular syphilis. Seventy-five ocular or non-ocular specimens from 55 ocular syphilis patients in 14 states within the United States were collected between February 2016 and November 2020. Sufficient T. pallidum DNA was available from nine patients for genotyping and three for WGS. Genotyping was done using the augmented Centers for Disease Control and Prevention typing scheme, and WGS was performed on Illumina platforms. Multilocus sequence typing allelic profiles were predicted from whole genome sequence data. T. pallidum DNA was detected in various specimens from 17 (30.9%) of the 55 patients, and typing was done on samples from 9 patients. Four complete strain types (14d10/g, 14b9/g, 14d9/g, and 14e9/f) and five partial types were identified. WGS was successful on samples from three patients and all three strains belonged to the SS14 clade of T. pallidum. Our data reveal that multiple strain types are associated with ocular manifestations of syphilis. While genotyping and WGS were challenging due to low amounts of T. pallidum DNA in specimens, we successfully performed WGS on cerebrospinal fluid, vitreous fluid, and whole blood.IMPORTANCESyphilis is caused by the spirochete Treponema pallidum. Total syphilis rates have increased significantly over the past two decades in the United States, and the disease remains a public health concern. In addition, ocular syphilis cases has also been on the rise, coinciding with the overall increase in syphilis rates. We conducted a molecular investigation utilizing traditional genotyping and whole genome sequencing over a 5-year period to ascertain if specific T. pallidum strains are associated with ocular syphilis. Genotyping and phylogenetic analysis show that multiple T. pallidum strain types are associated with ocular syphilis in the United States.

Clinical Evaluation of a New Chemiluminescence Assay for the Detection of Treponema Pallidum Antibodies.

BACKGROUND: A new chemiluminescence assay, the Anti-TP-Ⅱ assay, is going to be commercially available in clinical laboratories in China and other countries. This study examined the performance of the new assay for the detection of TP infection and compared it with that of the Anti-TP assay by using large amounts of clinical samples. METHODS: The precision, accuracy, anti-interference ability, and the clinical sensitivity and specificity of the Anti-TP-Ⅱ assay were evaluated. In addition, compared with those of the Anti-TP assay, the false positive and false negative rates of the Anti-TP-Ⅱ assay were evaluated for 2,436 clinical routine samples and 711 preselected Anti-TP assay reactive samples. Discrepancy of the samples was investigated with the recomLinec Treponema IgM/IgG kit or the Elecsys syphilis assay. RESULTS: The precision, accuracy, and anti-interference ability of the Anti-TP-Ⅱ assay met the national standard of China, and there was an overall agreement of 96.75% (Kappa = 0.91) between the two assays. The sensitivity and specificity of the Anti-TP-Ⅱ assay were 100% (95% CI: 94.13% to 100%) and 99.92% (95% CI: 99.70% to 99.99%), respectively. Compared with the Anti-TP assay, the Anti-TP-Ⅱ assay significantly reduced the number of borderline samples and the false positive rate. CONCLUSIONS: Considering its excellent performance, the Anti-TP-Ⅱ assay is a good screening test for high-throughput laboratories and can replace the previous generation of reagents, the Anti-TP assay, with a superior specificity.

The hare syphilis agent is related to, but distinct from, the treponeme causing rabbit syphilis.

The treponemes infecting lagomorphs include Treponema paraluisleporidarum ecovar Cuniculus (TPeC) and ecovar Lepus (TPeL), infecting rabbits and hares, respectively. In this study, we described the first complete genome sequence of TPeL, isolate V3603-13, from an infected mountain hare (Lepus timidus) in Sweden. In addition, we determined 99.0% of the genome sequence of isolate V246-08 (also from an infected mountain hare, Sweden) and 31.7% of the genome sequence of isolate Z27 A77/78 (from a European hare, Lepus europeaus, The Netherlands). The TPeL V3603-13 genome had considerable gene synteny with the TPeC Cuniculi A genome and with the human pathogen T. pallidum, which causes syphilis (ssp. pallidum, TPA), yaws (ssp. pertenue, TPE) and endemic syphilis (ssp. endemicum, TEN). Compared to the TPeC Cuniculi A genome, TPeL V3603-13 contained four insertions and 11 deletions longer than three nucleotides (ranging between 6 and2,932 nts). In addition, there were 25 additional indels, from one to three nucleotides long, altogether spanning 36 nts. The number of single nucleotide variants (SNVs) between TPeC Cuniculi A and TPeL V3603-13 were represented by 309 nucleotide differences. Major proteome coding differences between TPeL and TPeC were found in the tpr gene family, and (predicted) genes coding for outer membrane proteins, suggesting that these components are essential for host adaptation in lagomorph syphilis. The phylogeny revealed that the TPeL sample from the European brown hare was more distantly related to TPeC Cuniculi A than V3603-13 and V246-08.

Clinical and genomic diversity of Treponema pallidum subspecies pallidum to inform vaccine research: an international, molecular epidemiology study.

BACKGROUND: The increase in syphilis rates worldwide necessitates development of a vaccine with global efficacy. We aimed to explore Treponema pallidum subspecies pallidum (TPA) molecular epidemiology essential for vaccine research by analysing clinical data and specimens from early syphilis patients using whole-genome sequencing (WGS) and publicly available WGS data. METHODS: In this multicentre, cross-sectional, molecular epidemiology study, we enrolled patients with primary, secondary, or early latent syphilis from clinics in China, Colombia, Malawi, and the USA between Nov 28, 2019, and May 27, 2022. Participants aged 18 years or older with laboratory confirmation of syphilis by direct detection methods or serological testing, or both, were included. Patients were excluded from enrolment if they were unwilling or unable to give informed consent, did not understand the study purpose or nature of their participation, or received antibiotics active against syphilis in the past 30 days. TPA detection and WGS were conducted on lesion swabs, skin biopsies, skin scrapings, whole blood, or rabbit-passaged isolates. We compared our WGS data to publicly available genomes and analysed TPA populations to identify mutations associated with lineage and geography. FINDINGS: We screened 2802 patients and enrolled 233 participants, of whom 77 (33%) had primary syphilis, 154 (66%) had secondary syphilis, and two (1%) had early latent syphilis. The median age of participants was 28 years (IQR 22-35); 154 (66%) participants were cisgender men, 77 (33%) were cisgender women, and two (1%) were transgender women. Of the cisgender men, 66 (43%) identified as gay, bisexual, or other sexuality. Among all participants, 56 (24%) had HIV co-infection. WGS data from 113 participants showed a predominance of SS14-lineage strains with geographical clustering. Phylogenomic analyses confirmed that Nichols-lineage strains were more genetically diverse than SS14-lineage strains and clustered into more distinct subclades. Differences in single nucleotide variants (SNVs) were evident by TPA lineage and geography. Mapping of highly differentiated SNVs to three-dimensional protein models showed population-specific substitutions, some in outer membrane proteins (OMPs) of interest. INTERPRETATION: Our study substantiates the global diversity of TPA strains. Additional analyses to explore TPA OMP variability within strains is vital for vaccine development and understanding syphilis pathogenesis on a population level. FUNDING: US National Institutes of Health National Institute for Allergy and Infectious Disease, the Bill & Melinda Gates Foundation, Connecticut Children's, and the Czech Republic National Institute of Virology and Bacteriology.

Treponema pallidum genetic diversity and its implications for targeted vaccine development: A cross-sectional study of early syphilis cases in Southwestern Colombia.

BACKGROUND: Venereal syphilis, caused by the spirochete Treponema pallidum subsp. pallidum (TPA), is surging worldwide, underscoring the need for a vaccine with global efficacy. Vaccine development requires an understanding of syphilis epidemiology and clinical presentation as well as genomic characterization of TPA strains circulating within at-risk populations. The aim of this study was to describe the clinical, demographic, and molecular features of early syphilis cases in Cali, Colombia. METHODS AND FINDINGS: We conducted a cross-sectional study to identify individuals with early syphilis (ES) in Cali, Colombia through a city-wide network of public health centers, private sector HIV clinics and laboratory databases from public health institutions. Whole blood (WB), skin biopsies (SB), and genital and oral lesion swabs were obtained for measurement of treponemal burdens by polA quantitative polymerase chain reaction (qPCR) and for whole-genome sequencing (WGS). Among 1,966 individuals screened, 128 participants met enrollment criteria: 112 (87%) with secondary (SS), 15 (12%) with primary (PS) and one with early latent syphilis; 66/128 (52%) self-reported as heterosexual, while 48 (38%) were men who have sex with men (MSM). Genital ulcer swabs had the highest polA copy numbers (67 copies/µl) by qPCR with a positivity rate (PR) of 73%, while SS lesions had 42 polA copies/µl with PR of 62%. WB polA positivity was more frequent in SS than PS (42% vs 7%, respectively; p = 0.009). Isolation of TPA from WB by rabbit infectivity testing (RIT) was achieved in 5 (56%) of 9 ES WB samples tested. WGS from 33 Cali patient samples, along with 10 other genomic sequences from South America (9 from Peru, 1 from Argentina) used as comparators, confirmed that SS14 was the predominant clade, and that half of all samples had mutations associated with macrolide (i.e., azithromycin) resistance. Variability in the outer membrane protein (OMP) and vaccine candidate BamA (TP0326) was mapped onto the protein's predicted structure from AlphaFold. Despite the presence of mutations in several extracellular loops (ECLs), ECL4, an immunodominant loop and proven opsonic target, was highly conserved in this group of Colombian and South American TPA isolates. CONCLUSIONS: This study offers new insights into the sociodemographic and clinical features of venereal syphilis in a highly endemic area of Colombia and illustrates how genomic sequencing of regionally prevalent TPA strains can inform vaccine development.

Treponema pallidum protein Tp0136 promotes angiogenesis to facilitate the dissemination of Treponema pallidum.

The incompletely eliminated Treponema pallidum (T. pallidum) during primary syphilis chancre infection can result in the progression of secondary, tertiary, or latent syphilis in individuals, suggesting that T. pallidum has successfully evaded the immune response and spread to distant sites. The mechanism underlying the dissemination of T. pallidum is unclear. Here, a syphilitic rabbit model dorsal-injected with recombinant Tp0136 protein or Tp0136 antibody subcutaneously was used to demonstrate the role of Tp0136 protein in promoting the dissemination of T. pallidum to the testis and angiogenesis in vivo; vascular endothelial cell line HMEC-1 was employed to display that Tp0136 protein enhances the angiogenesis. Furthermore, the three-dimensional microfluidic angiogenesis system showed that the angiogenesis would heighten vascular permeability. Then transcriptome sequencing analysis, in conjunction with cell-level validation, elucidated the critical role of the PI3K-AKT signaling pathway in the promotion of angiogenesis by Tp0136 protein, resulting in heightened permeability. These findings elucidate the strategy employed by T. pallidum in evading immune clearance.

Majority of Treponema pallidum ssp. pallidum MLST allelic profiles in the Czech Republic (2004-2022) belong to two SS14-like clusters.

Syphilis is a multistage sexually transmitted disease caused by Treponema pallidum ssp. pallidum. In the Czech Republic, there are around 700-800 new syphilis cases annually, continuously increasing since 2012. This study analyzed a total of 1228 samples from 2004 to 2022. Of the PCR-positive typeable samples (n = 415), 68.7% were fully-typed (FT), and 31.3% were partially-typed. Most of the identified isolates belonged to the SS14-clade and only 6.3% were the Nichols-like cluster. While in the beginning of sample collection isolates have been macrolide-susceptible, recent isolates are completely resistant to macrolides. Among the FT samples, 34 different allelic profiles (APs) were found. Most of the profiles (n = 27) appeared just once in the Czech population, while seven profiles were detected more than twice. The most frequent APs belonged to two separate groups of SS14-like isolates, including group of 1.3.1 (ST 1) and 1.26.1 (ST 25) profiles, and the second group containing 1.1.8 (ST 3), 1.1.1 (ST 2), and 1.1.3 (ST 11) (representing 57.5%, and 25.3% of all detected APs, respectively). Both groups consistently differed in 6 nucleotide positions in five genes (TP0150, TP0324, TP0515, TP0548, and TP0691) coding amino-acid replacements suggesting that one or more of these differences could be involved in the higher success of the first group.

A Novel Treponema pallidum Subspecies pallidum Strain Associated With a Painful Oral Lesion Is a Member of a Potentially Emerging Nichols-Related Subgroup.

BACKGROUND: Early syphilitic lesions are typically painless; however, several recent case studies have included patients with tender lesions and no evidence of concurrent infections. Here we present the manifestations and serological and molecular findings of a patient from New York State with a painful tongue lesion. METHODS: The diagnosis of syphilis was based on a combination of physical examination, serologic, pathologic, and immunohistochemical findings. DNA obtained from a formalin-fixed, paraffin-embedded biopsy was used to characterize the infecting pathogen using polymerase chain reaction, multilocus sequence typing, and whole-genome sequencing methods. RESULTS: Polymerase chain reaction and multilocus sequence typing of the biopsy specimen confirmed infection with T. pallidum subspecies pallidum ( T. pallidum ) of the Nichols cluster. Whole-genome sequencing analysis of this strain (herein called NYMC01) showed that it contained 17 unique single nucleotide variations and 4 more complex genetic differences; this novel genotype matched only 2 specimens, both from a patient in Seattle, Washington. The presence of this rare genotype in 2 geographically distinct locations suggests the potential emergence and spread of a new subgroup of the Nichols cluster. CONCLUSIONS: To our knowledge, this is the first genomic sequence obtained from a T. pallidum strain linked to a painful lesion, and the third description of whole-genome sequencing of T. pallidum from formalin-fixed, paraffin-embedded tissue. Analysis of additional specimens may reveal that the NYMC01-related genotype represents an emerging T. pallidum subgroup and may also aid in determining whether the painful clinical presentation of primary syphilis is related to specific T. pallidum genotypes.

The effect of daily usage of Listerine Cool Mint mouthwash on the oropharyngeal microbiome: a substudy of the PReGo trial.

Introduction. ListerineÒ is a bactericidal mouthwash widely used to prevent oral health problems such as dental plaque and gingivitis. However, whether it promotes or undermines a healthy oral microbiome is unclear.Hypothesis/Gap Statement. We hypothesized that the daily use of Listerine Cool Mint would have a significant impact on the oropharyngeal microbiome.Aim. We aimed to assess if daily usage of Listerine Cool Mint influenced the composition of the pharyngeal microbiome.Methodology. The current microbiome substudy is part of the Preventing Resistance in Gonorrhoea trial. This was a double-blind single-centre, crossover, randomized controlled trial of antibacterial versus placebo mouthwash to reduce the incidence of gonorrhoea/chlamydia/syphilis in men who have sex with men (MSM) taking HIV pre-exposure prophylaxis (PrEP). Fifty-nine MSM taking HIV PrEP were enrolled. In this crossover trial, participants received 3 months of daily Listerine followed by 3 months of placebo mouthwash or vice versa. Oropharyngeal swabs were taken at baseline and after 3 months use of each mouthwash. DNA was extracted for shotgun metagenomic sequencing (Illumina Inc.). Non-host reads were taxonomically classified with MiniKraken and Bracken. The alpha and beta diversity indices were compared between baseline and after each mouthwash use. Differentially abundant bacterial taxa were identified using ANOVA-like differential expression analysis.Results. Streptococcus was the most abundant genus in most samples (n = 103, 61.7 %) with a median relative abundance of 31.5% (IQR 20.6-44.8), followed by Prevotella [13.5% (IQR 4.8-22.6)] and Veillonella [10.0% (IQR 4.0-16.8)]. Compared to baseline, the composition of the oral microbiome at the genus level (beta diversity) was significantly different after 3 months of Listerine (P = 0.006, pseudo-F = 2.29) or placebo (P = 0.003, pseudo-F = 2.49, permutational multivariate analysis of variance) use. Fusobacterium nucleatum and Streptococcus anginosus were significantly more abundant after Listerine use compared to baseline.Conclusion. Listerine use was associated with an increased abundance of common oral opportunistic bacteria previously reported to be enriched in periodontal diseases, oesophageal and colorectal cancer, and systemic diseases. These findings suggest that the regular use of Listerine mouthwash should be carefully considered.

Metagenomic and paleopathological analyses of a historic documented collection explore ancient dental calculus as a diagnostic tool.

Dental calculus is a microbial biofilm that contains biomolecules from oral commensals and pathogens, including those potentially related to cause of death (CoD). To assess the utility of calculus as a diagnostically informative substrate, in conjunction with paleopathological analysis, calculus samples from 39 individuals in the Smithsonian Institution's Robert J. Terry Collection with CoDs of either syphilis or tuberculosis were assessed via shotgun metagenomic sequencing for the presence of Treponema pallidum subsp. pallidum and Mycobacterium tuberculosis complex (MTBC) DNA. Paleopathological analysis revealed that frequencies of skeletal lesions associated with these diseases were partially inconsistent with diagnostic criteria. Although recovery of T. p. pallidum DNA from individuals with a syphilis CoD was elusive, MTBC DNA was identified in at least one individual with a tuberculosis CoD. The authenticity of MTBC DNA was confirmed using targeted quantitative PCR assays, MTBC genome enrichment, and in silico bioinformatic analyses; however, the lineage of the MTBC strain present could not be determined. Overall, our study highlights the utility of dental calculus for molecular detection of tuberculosis in the archaeological record and underscores the effect of museum preparation techniques and extensive handling on pathogen DNA preservation in skeletal collections.

Uncovering the mechanisms of host mitochondrial cardiolipin release in syphilis: Insights from human microvascular endothelial cells.

The release of host mitochondrial cardiolipin is believed to be the main factor that contributes to the production of anti-cardiolipin antibodies in syphilis. However, the precise mechanism by which mitochondria release cardiolipin in this context remains elusive. This study aimed to elucidate the mechanisms underlying mitochondrial cardiolipin release in syphilis. We conducted a cardiolipin quantitative assay and immunofluorescence analysis to detect mitochondrial cardiolipin release in human microvascular endothelial cells (HMEC-1), with and without Treponema pallidum (Tp) infection. Furthermore, we explored apoptosis, a key mechanism for mitochondrial cardiolipin release. The potential mediator molecules were then analyzed through RNA-sequence and subsequently validated using in vitro knockout techniques mediated by CRISPR-Cas9 and pathway-specific inhibitors. Our findings confirm that live-Tp is capable of initiating the release of mitochondrial cardiolipin, whereas inactivated-Tp does not exhibit this capability. Additionally, apoptosis detection further supports the notion that the release of mitochondrial cardiolipin occurs independently of apoptosis. The RNA-sequencing results indicated that microtubule-associated protein2 (MAP2), an axonogenesis and dendrite development gene, was up-regulated in HMEC-1 treated with Tp, which was further confirmed in syphilitic lesions by immunofluorescence. Notably, genetic knockout of MAP2 inhibited Tp-induced mitochondrial cardiolipin release in HMEC-1. Mechanically, Tp-infection regulated MAP2 expression via the MEK-ERK-HES1 pathway, and MEK/ERK phosphorylation inhibitors effectively block Tp-induced mitochondrial cardiolipin release. This study demonstrated that the infection of live-Tp enhanced the expression of MAP2 via the MEK-ERK-HES1 pathway, thereby contributing to our understanding of the role of anti-cardiolipin antibodies in the diagnosis of syphilis.

Analysis of molecular subtypes and antibiotic resistance in Treponema pallidum isolates from blood donors in Khyber Pakhtunkhwa, Pakistan.

Syphilis, caused by Treponema pallidum, is resurging globally. Molecular typing allows for the investigation of its epidemiology. In Pakistan and other nations, T. pallidum subsp. pallidum has developed widespread macrolide resistance in the past decade. A study at the Peshawar Regional Blood Centre from June 2020-June 2021 analyzed serum samples from 32,812 blood donors in Khyber Pakhtunkhwa, Pakistan, to assess circulating T. pallidum strains and antibiotic resistance. Blood samples were initially screened for T. pallidum antibodies using a chemiluminescent microparticle immunoassay (CMIA). CMIA-reactive samples underwent polymerase chain reaction (PCR) targeted the polA, tpp47, bmp, and tp0319 genes. PCR-positive samples were further analyzed for molecular subtyping using a CDC-developed procedure and tp0548 gene examination. All PCR-positive samples were analyzed for the presence of point mutations A2058G and A2059G in 23S rRNA, as well as the G1058C mutation in 16S rRNA. These mutations are known to impart antimicrobial resistance to macrolides and doxycycline, respectively. Out of 32,812 serum samples, 272 (0.83%) were CMIA-reactive, with 46 being PCR-positive. Nine T. pallidum subtypes were identified, predominantly 14d/f. The A2058G mutation in 23S rRNA was found in 78% of cases, while G1058C in 16S rRNA and A2059G in 23S rRNA were absent. The research found donor blood useful for assessing T. pallidum molecular subtypes and antibiotic resistance, especially when chancres are not present. The prevalent subtype was 14d/f (51.85%), and the high macrolide resistance of 36 (78%) indicates caution in using macrolides for syphilis treatment in Khyber Pakhtunkhwa, Pakistan.